title: Three-dimensional magnetization-prepared imaging using a concentric cylinders trajectory.
abstract: OBJECTIVE
  To develop new magnetization-prepared imaging schemes based on a three-dimensional (3D) concentric cylinders trajectory.
  
  
  METHODS
  The 3D concentric cylinders trajectory, which is robust to off-resonance effects and timing delays while requiring fewer excitations than a comparable 3D Cartesian (3DFT) sequence, is used as the readout for magnetization-prepared sequences exploiting its inherently centric-ordered structure. Two applications: (i) T1 -weighted brain imaging with an inversion-recovery-prepared radiofrequency-spoiled gradient-echo (IR-SPGR) sequence, (ii) non-contrast-enhanced (NCE) peripheral angiography with a magnetization-prepared balanced steady-state free precession (bSSFP) sequence are presented to demonstrate the effectiveness of the proposed method. For peripheral angiography, the scan efficiency is further improved by interleaving different preparations at different rates and by carefully designing the sampling geometry for an efficient parallel imaging method.
  
  
  RESULTS
  In vivo brain scans with an IR-SPGR sequence and lower extremity scans with a magnetization-prepared bSSFP sequence for NCE peripheral angiography both demonstrate that the proposed sequences with concentric cylinders effectively capture the transient magnetization-prepared contrast with faster scan times than a corresponding 3DFT sequence. The application of peripheral angiography also shows the feasibility of the proposed interleaving schemes and parallel imaging method.
  
  
  CONCLUSIONS
  The 3D concentric cylinders trajectory is a robust and efficient readout that is well-suited for magnetization-prepared imaging.
authors.affiliation: Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA.
authors.forename: Kie Tae
authors.initials: KT
authors.lastname: Kwon
authors.forename: Holden H
authors.initials: HH
authors.lastname: Wu
authors.forename: Taehoon
authors.initials: T
authors.lastname: Shin
authors.forename: Tolga
authors.initials: T
authors.lastname: Cukur
authors.forename: Michael
authors.initials: M
authors.lastname: Lustig
authors.forename: Dwight G
authors.initials: DG
authors.lastname: Nishimura
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009716:Numerical Analysis, Computer-Assisted; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: 3D concentric cylinders; magnetization-prepared imaging; non-Cartesian trajectories